1. Field of the Invention
The present invention relates to an optical disk apparatus for optically recording information, and, more particularly, to an optical disk apparatus which reliably executes an information interchange process of an optical disk.
2. Description of the Related Art
Conventionally, an information recording/reproduction apparatus for use in an optical disk apparatus for recording information on, and reproducing it from, a data recording medium, such as a rewritable type or WORM (Write once read many) type optical disk, is designed so that an optical head, which is linearly movable in the radial direction of the optical disk by a linear motor, irradiates light on the optical disk for information recording or information reproduction.
According to the prior art optical disk apparatus, a foreign matter stuck on the surface of an optical disk or a scratch made thereon is likely to hinder the proper data recording or reproduction. In such a case, when the optical head accesses to that area where data recording or reproduction is not possible, a so-called information interchange process is carried out to use a proper area instead of the improper area. This information interchange process is executed when "read-after-write" is performed at the time of recording data and a reading ratio (error ratio) at the reading time is equal to or greater than a predetermined value. The "read-after-write" is a temporary reproduction immediately after data recording in order to check if the written data is properly recorded.
When information is recorded on an area where foreign matter is stuck or a scratch is made or on the vicinity thereof and the "read-after-write" is then executed, information may or may not be reproduced due to the unstable amplitude of the reproduced signal. When information is reproduced, the information interchange process will not be performed even if it has been improperly written, then later information reproduction would not probably be possible.